The scanning probe microscope is a general term referring to various mechanisms and methods in which a sample is scanned with a microscopic probe to produce much higher resolutions than can be achieved with standard optical microscopes. One common example is the atomic force microscope, also known as the scanning force microscope that scans a sharp stylus attached to a flexible spring lever, commonly called a cantilever, over a sampled surface. This very high resolution atomic force microscope has a demonstrated resolution of fractions of a nanometer more than one thousand times better than the optical diffraction limit. The basic objective of the operation of the atomic force microscope is to measure the forces at the atomic level between a sharp probing tip and a sample surface. Surface areas of interest to be examined by the atomic force microscope are of the order of surface topographies within nanoscales or ten to the minus tenth meters. Computer programs are utilized to produce images of surface topography of samples of interest. Under normal operating conditions, an atomic force microscope tip may last for a few days, so changing a probe tip may become a regular occurrence.
The relevant prior art related to atomic force microscopes includes U.S. Pat. No. 5,705,814 to James M. Young, et al. for Scanning Probe Microscope Having Automatic Probe Exchange and Alignment, issued Jan. 6, 1998. This patent to Young, et al. points out the importance of precise and accurate alignment of probes with respect to a workpiece sample to be examined.
A U.S. Pat. No. 6,032,518, issued to Prater, et al. for Scanning Stylus Atomic Force Microscope With Cantilever Tracking and Optical Access, issued Mar. 7, 2000. This prior art patent provides important background information with respect to the operation of the atomic force microscope and further points out the importance of precise and accurate alignment of the probe tip with respect to a sample to be examined.
The U.S. Pat. No. 5,388,452, to Harp, et al. for Detection Systems for Atomic Force Microscopes, issued Feb. 14, 1995, also provides further interesting and informative background information with respect to the operations of the atomic force microscope system.
Of additional interest is U.S. Pat. No. 5,672,816, to Park, et al. for Large Stage System for Scanning Probe Microscopes and Other Instruments, issued Sep. 30, 1997. The definitions provided by this very informative document are very helpful in understanding the technology that underlies all scanning probe systems.
The U.S. Pat. No. 6,737,646 B2, to Schwartz for Enhanced Scanning Probe Microscope and Nanolithographic Methods Using the Same issued May 18, 2004, is of particular interest. In this patent document the inventor has emphasized the inclusion of optical microscopes in commercial scanning probe microscopes to help monitor the tip to sample approach and to select the areas of interest on the sample surface. In addition, the inventor has shown an application in which the sample tip may be viewed from the side by the utilization of a small right angle mirror for the optical microscope.
These prior art innovations and their methods are commendable and show a creative spirit. These prior art innovations and systems, however, do not include those elements of the instant invention that provide a long felt but unmet need in the art. None of the prior art has used the direct viewing of the probe tip itself as a means for positioning and aligning that probe tip with respect to a sample work piece of interest.